The invention provides an optical disk drive. In one embodiment, the optical disk drive comprises a feeding device, a power driver, and a controller. The feeding device comprises a spherical aberration (SA) lens and a stepping motor, wherein the SA lens corrects spherical aberration of a light beam emitted by a pickup head, and the stepping motor moves the SA lens according to a plurality of control signals. The power driver generates the control signals to drive the stepping motor to move the SA lens. The controller directs the power driver to drive the stepping motor to move the SA lens with only stable steps when the SA lens is required to move, so that the stepping motor is in a stable state without inducing step errors after the stepping motor rotates with the stable steps.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An optical disk drive, comprising: a feeding device, comprising a spherical aberration (SA) lens and a stepping motor, wherein the SA lens is capable of correcting spherical aberration of a light beam emitted by a pickup head, and the stepping motor is capable of moving the SA lens according to a plurality of control signals; a power driver, coupled to the feeding device, capable of generating the control signals to drive the stepping motor to move the SA lens; and a controller, coupled to the power driver, capable of driving the stepping motor with only stable steps through the power driver during a driving excitation; wherein the stepping motor does not substantially rotate when there is no driving excitation; wherein when the feeding device is initiated for a first time, the controller directs the stepping motor to move the SA lens to a stepping motor stable point near a reference position, wherein the stepping motor is in the stable state without inducing step errors when the stepping motor moves the SA lens to the stepping motor stable point.
2. The optical disk drive as claimed in claim 1 , wherein the stable steps comprise an even number of steps.
3. The optical disk drive as claimed in claim 1 , wherein the controller first drives the stepping motor to move the SA lens to the reference position, then determines whether the stepping motor is in the stable state, and then directs the stepping motor to move the SA lens with at least one extra step to stabilize the stepping motor when the stepping motor is not in the stable state, thus directing the stepping motor to move the SA lens to the stepping motor stable point.
4. The optical disk drive as claimed in claim 1 , wherein the controller first drives the stepping motor to move the SA lens to the reference position, then determines whether the stepping motor is in the stable state, and then adjusts phases of the control signals to stable phases for stabilizing the stepping motor when the stepping motor is not in the stable state, thus directing the stepping motor to move the SA lens to the stepping motor stable point.
5. The optical disk drive as claimed in claim 1 , wherein the controller determines whether the stepping motor is in the stable state by checking phases of the control signals generated by the power driver.
6. The optical disk drive as claimed in claim 1 , wherein when the SA lens is required to move for a first time and the stepping motor has step errors generated during initiation, the controller directs the power driver to generate the control signals with phases of initial excitation patterns for step error correction before moving the SA lens.
7. The optical disk drive as claimed in claim 6 , wherein the initial excitation patterns are the same as the phases of the control signals at a last step of a prior driving of the stepping motor.
8. The optical disk drive as claimed in claim 1 , wherein the optical disk drive does not comprise a home sensor, and the controller directs the feeding device to move the SA lens until the SA lens is moved to a position with a greatest movable distance where the SA lens cannot be moved any farther, and then determines the reference position according to the position with the greatest movable distance.
9. A method for driving a feeding device of an optical disk drive, wherein the feeding device comprises a spherical aberration (SA) lens and a stepping motor, the SA lens corrects spherical aberration of a light beam emitted by a pickup head, and the stepping motor moves the SA lens according to a plurality of control signals generated by a power driver, comprising: when the feeding device is initiated for a first time, directing the stepping motor to move the SA lens to a stepping motor stable point near a reference position, wherein the stepping motor is in the stable state without inducing step errors when the stepping motor moves the SA lens to the stepping motor stable point; and driving the stepping motor with only stable steps during a driving excitation to move the SA lens; wherein the stepping motor does not substantially rotate when there is no driving excitation.
10. The method as claimed in claim 9 , wherein the stable steps comprise an even number of steps.
11. The method as claimed in claim 9 , wherein directing the stepping motor to move the SA lens to the stepping motor stable point comprises: driving the stepping motor to move the SA lens to the reference position; determining whether the stepping motor is in the stable state; when the stepping motor is not in the stable state, directing the stepping motor to move the SA lens with at least one extra step to stabilize the stepping motor.
12. The method as claimed in claim 9 , wherein directing the stepping motor to move the SA lens to the stepping motor stable point comprises: driving the stepping motor to move the SA lens to the reference position; determining whether the stepping motor is in the stable state; and when the stepping motor is not in the stable state, adjusting phases of the control signals to stable phases for stabilizing the stepping motor.
13. The method as claimed in claim 9 , wherein the method further comprises checking phases of the control signals generated by the power driver to determine whether the stepping motor is in the stable state.
14. The method as claimed in claim 9 , wherein the method further comprises when the SA lens is required to move for a first time and the stepping motor has step errors generated during initiation, directing the power driver to generate the control signals with phases of initial excitation patterns for step error correction before moving the SA lens.
15. The method as claimed in claim 14 , wherein the initial excitation patterns are the same as the phases of the control signals at a last step of a prior driving of the stepping motor.
16. The method as claimed in claim 9 , wherein the optical disk drive does not comprise a home sensor, and the method further comprises directing the feeding device to move the SA lens until the SA lens is moved to a position with a greatest movable distance where the SA lens cannot be moved any farther, and determining the reference position according to the position with the greatest movable distance.
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November 21, 2008
March 26, 2013
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